Scanning device



Sept. 29, 1931. A. o. TATE SCANNING DEVICE Filed May 22, 1929 PatentedSept. 29, 1931 r ALFRED ORDE TATE, OF TORONTO, ONTARIO, CANADA SCANNINGDEVIGE Application filed May 22,

This invention relates to improvements in scanning devices and mountingsfor same, to be used in the art of television, as described in thepresent specification and illustrated in the accompanying drawings whichform part of same.

The invention'consists essentially of a novel mounting for a scanningband and partlcularly "a scanning band similar to that de scribedandclaimed in my United States application, Serial No. 336,226, filed January 30, 1929. v

In the above mentioned application I described and claimed an aperturedband or belt lead over a driving drum and an idler drum. The aperturesin a scanning device are preferably arranged in such a manner that onlyone aperture at one time will scan or register on the image to bescanned. In

view of this, the size of the image which could beefi'ectively scannedby means of the above mentioned apertured band is somewhat limited, asit requires a certain number of apertures to scan each vertical inch,providing the scanning action is in a substantially horizontaldirection, and these apertures are preferably laterally spaced from eachother a'distance equal to or greater than the width of the area to bescanned. Supposing the surface to be scanned was four inches in widthand it required twenty apertures to scan each vertical inch of area.

Thus to completely scan this image from bottom to top or top to bottom,a band of approximately'one hundred and sixty inches in length would berequired, having eighty apertures therethrough, each spaced from itsneighbouring aperture by a distance of four inches, and inorder to scanthe image completely from bottom to top and top to bottom" to effect anundulatory scanning movement sodesired in television,it would require aband of twice this length, or approximately three hundred and twentyinches. It is quite evident that a band of this length would requireconsiderable space to accommodate it if it were mounted over a singledriving drumand an idler drum. In the following specification anddrawings,- I show another method of mounting the scan- 1929. Serial No.365,031.

ning band whereby an endless band of indefinite length may be mountedanddrivenin a relatively small space, thus rendering it quite feasiblefor portable or stationary radio transmittingor receiving sets. I Thechief objects oftheinvention, there fore, are to construct and arrange amount ing for a scanning band or belt whereby a relatively long scanningband may be mounted in a small space and whereby the entire no band maybe kept in motion at the same time; to appreciably increase the size ofthe scanning area or the image that may be scanned by an endlessapertured scanning'belt without materially increasing the space requiredfor mounting said belt; to prevent undue strain at any point in arelatively long scanning belt; to maintain the tension on the beltpractically uniform throughout its length; to provide a scanning devicecapable of scanning relatively large images for any desired period oftime; to facilitate the synchronizing of a receiving scanning devicewith a transmitting scanning device by causing the scanning action ofeach set to be continuous 7 regardless of the size of the image to betransmitted; and generally to provide a scanning device particularlyadaptedforuse in the radio transmission and receptionef relative= lylarge images, simple in its constructional 3 details and in operationand capable of accomplishing the aforesaid results and purposes. 1 Inthe drawings, Figure 1 is a plan view of the invention. q 1

Fig'ure'2 is a front'elevational view of Figure 1. 'Like numerals ofreference indicate'corre sponding partsin the various figures. i

Referring to the drawings, the numeral 10 indicates a suitable frameworkcapable of supporting the various mechanisms involved in this invention.11 is a" cylinder or drum mounted on a spindle 12 journalled ndsupported in the frame 10" as at 13. "14$ is a cylinder or drum similarto'thatshown atll and parallel therewith and mounted in the same planeas said cylinder 11 on a shaft 15 journalled in the frame 10 as at 16.Driving gears 17 and 18 rigid in respectto the drums 10 11 and 14;respectively, are mounted on the shafts 12 and 15, respectively. driveshaft 19 suitably driven is ournalled in the frame 10 as at 20 and hasgears 21 co-acting with the gears 17 and 18. A plurality of pulleys ordrums 25 are mounted on shafts 26 journalled in the frame 10 as at 27.An endless apertured scanning band 30 is mounted over the drums 11, l land 25. The drums 25 are so mounted on the frame 10 that the band 30 inpassing over them will be led back and forth, as shown at 31. In thisway, a band of considerable length may be led over the different drumsor pulleys 25. The journal mountings for one or more of the drums may bereciprocally carried on the frame 10 as at 28 and suitable springs 29provided to impinge against the journals 28 to tension the band 30 andequalize the strain at all points, and also to prevent slaclcness of theband between any of the drums 25 or between the drums 11 andl l.

One or more of the drums 25 may be driven from the shaft 19, asillustrated at 25A, w iere a gear 35 rigid with the drum 25 meshes withand is driven by a gear 36 rigidly mounted on the shaft 19. It may befound advisable to drive either the drum 11 or the drum 14.- from theshaft 19 or to depend only on the driven drums as at 25A to actuate thescanning band 30 mounted thereon. The drums 25 insteadof being arrangedas shown could be arranged in tiers and the band 30 led over them in asimilar manner to that shown without changing the principles involved orgoing beyond the scope of this invention.

Suitable teeth 38 may be formed on the periphery of the driving drumsand corre sponding depressions or openings 39 adapted to be engaged bysaid teeth 38 may be formed in the band 30 to allow for a more positivedrive of the band 30. The teeth 88 and the depressions or openings 39are preferably so situated that they will not interfere in any way withthe scanning action of the band 80. Suitable guide flanges 40 may beprovided on any of the drums and positioned thereon to engage the edgesof the band 30 and to retain said band in its proper path. The drums 11and 14: are so mounted on the frame 10 that there will'be a spacebetween them as indicated at 42. The necessary electrical apparatus usedin the art of television as indicated at 43, may be placed in this spaceat l2. As it is desirable to accomplish the undulatory scanning motion,or in other words to scan the image from top to bottom and bottom to topin a continuous 'action, scanningapertures 44 are formed in the belt 30and are so arranged that each aperture will scan section of the imageadjacent the section scanned by the preceding aperture so that therewill be no break in the continuity of the scanning action. 1

One or more of the drums 25 may be driven from the shaft 19 asillustrated at 25A, where a gear rigid with the drum 25 meshes with andis driven by a gear 06 rigidly mounted on the shaft 19. 1t may be foundadvisable to drive either the drum 11 or the drum 1a from the shaft 19or to depend only on the driven drums as at 25A to actuate the scanningband 30 mounted thereon. The drums 25 instead of being arranged as showncould be arranged in tiers and the band 30 led over them in a similarmanner to that shown without changing the principles involved or goingbeyond the scope of this invention. Suitable teeth may be formed on theperiphery of the driving drum and corresponding depressions or openings39 adapted to be engaged by said teeth may be formed in the band 30 toallow for a more positive drive of the band 3 The teeth and thedepressions or openings 89 are preferably so situated that they will notinterfere in any way with the scanning action of the band 30. Suitableguide flanges 10 may be provided on any of the drums and positionedthereon to engage the edges of the band 30 and to retain said band inits proper path. 'lhe drums 1i and 1 1 are so mounted on the frame 10that there will be a space between them, as indicated at 12. Thenecessary electri 'ai apparatus used in the art of television asindicated at as, may be placed in this space is it is desirable toaccomplish the umlulatory scanning motion, or in other words to scan theimage from top to bottom and bottom to top in a continuous action, asaccomplished by my scanning belt described and claimed in my UnitedStates application Serial No. 336,226, filed January 30, 1929,

scanning apertures l are formed in the belt 30 and are so arranged thateach aperture will scan a section of the image adjacent the sectionscanned by the preceding aperture so that there will be no break in thecontinuity of the scanning action.

It is to be noted, however, that I do not wish to limit my invention tothe use of any particular form or arrangement of the apertures in thescanning band, as practically any form of endless scanning band could besuccessfully operated by means of this invention.

This invention in operation is particularly adapted for the radiotransmission and reception of relatively large images. The arrangementof the rotating drums 25 in diliercnt planes provides for the mountingthereon of an endless aperturci'l scanning band or belt of indefinitelength and, requires mininnuu space. The tensioned reciprocally mountedjournals for one or more of the drums 25 aids in retaining an eventension on the band ill) practically tlni-oughout its length andprevents sagging'at any point and particularly between the drums 11 and14. The teeth 88 on the driving drums engaging with the depressions oropenings 39 in the band 30 provides for a positive drive of the band 30,thereby eliminating any variation of speed and aiding the synchronism ofreceiving sets with transmitting sets. The rotating drums 25 may beincreased to an indefinite number and arranged either in rows or tiers,with the object of accommodating a belt of greater length to increasethe possible area that may be scanned without materially increasing thespace required.

Through these means, a belt of indefinite length may be successfullyoperated.

What I claim is:

1. In a scanning device for use in the art of television, two drumsrotatably mounted in the same plane on a frame and having a spacebetween them, a plurality of auxiliary drums. rotatably mounted inseparate rows and in the same plane, a flexible apertured endless beltled over said first-mentioned drums and back and forth over saidsecondmentioned drums, and additional means for positively rotating morethan two of said drums. V

2. In a scanning device for use in the art of television, a frame, twoparallel spaced drums rotatably mounted on said frame and in the sameplane, a plurality of drums rotatably mounted on said frame, an endlessflexible apertured band led over said firstmentioned drums and led oversaid secondmentioned drums, a mounting for certain of said drumsslidable in respect to said frame, and springs actuating said slidablemountings in the proper direction for tensioning said band.

3. In a scanning device for use in the art of television, a frame, twoparallel spaced drums rotatably mounted on said frame and in the sameplane, a plurality of parallel drums rotatably mounted on said frame, anendless flexible apertured band led over said first-mentioned drums andled over said sec- ALFRED ORDE TATE. V I

0nd mentioned drums, a shaft suitably jour- V nalled in said frame andhaving gears rigidly mounted thereon meshing with and drivingcorresponding gears on certain of said drums respectively, projectionson the periphery of said driven drums engaging depressions or openingsin said band, and resilient mountings for one or more of said secondmentioned drums providing means for tensioning said band.

l. A scanning device for use in the art of television comprising a pairof drums suitably journalled and spaced, a plurality of pulleysournalled at varying distances from said drums, an apertured belttrained around said drums and pulleys and reducing the reach of the belton the pulley to within a distance approximately even with the stretcharound said drums, and means for driving said belt. y

5. A scanning device for use in the art of

